Yun Shen Green Belt

1. 1
©MAHLE
SIXSIGMAANALYSIS
ON
COMPRESSIONVOLUME
MEASURMENT
YUNSHEN
APRIL2010
Team:
DonTobin,JoeFarrell,PedroDondele

2. 2
CASTINGANDCOMPRESSIONVOLUME
MEASUREMENTLOCATION
Define

3. 3
ProblemStatementWorksheet
Specific
(createstatementfromISportionofIs/IsNot
fromthebottomup)
Reducecustomerrejectionsforoutofspecificationcompressionvolumeon2-strokeand4-
strokecastingsproducedattheTrumbullPlantofthesmallenginecomponentsdivisionof
MAHLEEngineComponentsUSA,Inc.
Measurable(Documentthehistorical
performanceandgoals)
Rejectedpartsvalueoverlast3yearswas$153,146
whichis$51,049peryear.
Thevalueofpartsundercustomerdeviationwas
$902,835over3years.Sigmavaluewas1.507
Projectgoalistoreducetherejectvalue
by50%,eliminatecauseofdeviation
requests,andincreasesigmavalueto6.
Achievable(Validateestimatedproject
durationanddateswithaGanttchart)
EndofOctober2010
Relevant(Doesyourprojectsupportany
initiatives?Whatarethepotentialsavings?)
Supportscompanygoalof“Createsavingsof$500,000thatisnotinthecurrentbudget”
withanestimatedannualsavingof$25,000onrejectedpartsand$902,835onpotential
lossbyissueddeviation.
TimeBound(Sponsordate;compareto
Ganttchartforanyvariances)
EndofNovember2010
ProjectProblemStatement
Reducecustomerrejectionsforoutofspecificationcompressionvolumeon2-strokeand4-strokecastingsproducedatthe
TrumbullPlantofthesmallenginecomponentsdivisionofMAHLEEngineComponentsUSA,Inc.Thetargetistoreduce
customerrejectioncostby50%aswellaseliminatethepotentialforlosscausedbydeviationrequests.Thesigmavalueis
targetedon6.TheprojectwillbecompletedbyendofOctober2010andpresentedtothecustomerbyDecember2010.
Define

4. 4
ProjectProblemStatement
Reducecustomerrejectionsforoutofspecificationcompressionvolumeon2-strokeand4-strokecastingsproducedatthe
TrumbullPlantofthesmallenginecomponentsdivisionofMAHLEEngineComponentsUSA,Inc.Thetargetistoreduce
customerrejectioncostby50%aswellaseliminatethepotentialforlosscausedbydeviationrequests.Thesigmavalueis
targetedon6.TheprojectwillbecompletedbyendofOctober2010andpresentedtothecustomerbyDecember2010.
Charter
ProjectTeam
Core%TimeExtended%Time
YunShen20EdJones5
DonTobin10PedroFernandes5
JoeFarrell5
PedroDondele5
ProjectTimeline
PhaseEst.EndDate
Define4/20/10
Measure8/30/10
Analyze9/30/0
Improve10/30/10
Control11/30/10
Define

5. 5
Stakeholders(Identifynamesforeachfunctionalareaidentified)
SuppliersProcessOwnersCustomers
Rawmaterials
2-Strokecasting–DongLiPing/IKDSales
--DanaB/MTPPurchasing
--KlersonM./MTPBuyer
Incominginspector:
DonTobin
Support:
YunShen/QualityEngineer
MarleneM./QualityCoordinator
Nextstep
Stihl–Ben/IncomingInspection
Data&Information
MTP–KlersonM./Buyer
Downstream
HumanResources
DebbieM./HR
Consumer
FinancialResources
TJ/Controller
Regulatory
KeyMetrics
MeasurableInputs,xsProcessMetrics,xsandYs,ysMeasurableOutputs,Ys,ys
CompressionvolumestandardCompressionvolumemeasurementVolumespecificationfromStihldrawing
StakeholderAnalysis
Define

6. 6
CommunicationPlan
Communication
Topic
AudiencePurposeOwnerMediaFrequency
TollGateReviews
Sponsor,Finance,
Mentors
Toensureallresourcesand
supportareprovidedas
wellassteertheproject
intherightdirection
YunShenppt
Endofeach
DMAICphase
TeamMeetingsCoreTeam
Toensurethatallmembers
understandhis/her
responsesand
appropriatefeedback
YunShen
Meeting
note
s
EveryMonth
ExtendedTeam
Meetings
ExtendedandCore
Team
ToreviewprojectprogressYunShen
pptor
note
s
Asrequested
WeeklyProgress
Report
Define

7. 7
SIPOC
SupplierCustomerOutputProcessInput
•IKD
•Hirschmann
(Solarus
titrator)
•MTP
•Machinebore
•Cleanthe
casting
•Measure
volumeby
usingSolarus
titrator
•Recordthe
resultinreport
•Casting
•Volume
Measuring
instrument
•Fixture:1
sparkplug
•Fixture:2
boreplug
•Stihl•Reportof
result
•Acceptor
rejectthelot
Define

8. 8
DefinePhase:TollgateReview
DiscussedMeasuringplanwithEdJones(extendedteammember
andprojectadvisor)
Explainedtheprojectplantocoreteammembers.
Discussedmeasuringplan,methods,andtimelinetocoreteam
members.
ArrangedtestequipmentinplacetobereadyforMeasuring
phase.
Define

9. 9
HighLevelProcessMap
MALHE
Volume
Measure
IKD
Finished
Casting
ShiptoStihl
Stihl
Incoming
inspection
ShiptoMTP
MTP
Incoming
Inspection
Releaseto
Assemblyline
Deviation
ReturntoMTP
Scrap
Scrap
Stihl
Volume
Measure
IKD
Volume
Measure
Deviation
Measure

10. 10
ProjectBackground
HighLevelProcessMapshowsthesupplier,MTPandcustomerallhave“volume
measure”asakeyinspectionprocess.Severalquestionswereraised:
Didallthreepartiesusethesamemeasuringsystem?
Howcanwestandardizethemeasuringsystem?
Howdowejustifytherejectionisarealrepresentationofacastingdefect?
Whyarecastingsrejectedbythecustomerbutmeasuredasbeingin
specificationbyMAHLEoroursupplier?
Isthemeasuringsystem(instrument)goodenoughforthisvolumeinspection?
Measure

11. 11
ProcessingMap
MeasuringSystem
Mediausedin
apparatus
Procedure&
Standard
Fixture
Verification
Usingsame
Titrator?
Solarus
Titrator
Measure

12. 12
VolumeMeasurementFixturesVerification
ThreadGaugetube–perStihlSWN
43700-01
Keydimensionthataffectedvolume:
7.7+/-0.2Zeissmeasured7.72(in
spec).
Gaugepiston–perStihlSWN
43700-01
Keydimensionthataffectedvolume
38ZD26---81.498(inspec.)*
*Stihlhadissueswith38ZD26
7.7+/-0.2
38ZD26-81.500+/-0.005
Measure

13. 13
ProcessingMap
MeasuringSystem
Mediaused
inapparatus
Procedure
&Standard
VerifyfixtureUsingSame
Titrator?
Solarus
Titrator
Measure

14. 14
Standardized3partiesmeasuringsystems.MTPinvestigatedandtookactions
toeliminatethevariationbetweenIKD(supplier),MTP(MEHLE)and
Stihl(customer):
Mediausedin
apparatus
•MTPchangedtothe
IsopropylAlcoholthat
Stihl(customer)suggested.
Wealsorequestedthat
IKD(supplier)dothe
same.
Procedure&
Standard
•MTPreviewedand
adoptedcustomer
measurementstandardas
didoursuppliers.
•MTPreviewedandre-
calibratedfixtures
accordingtocustomer
standard,aswellasmade
sureoursuppliersdidthe
same.
UsingSame
Titrator?
•IKDandMTPpurchased
samevolumemeasuring
instruments(Solarus
DigitalTitrator)thatStihl
used.
Measure

15. 15
ProcessingMap
MeasuringSystem
Mediaused
inapparatus
Procedure&
Standard
VerifyfixtureUsingSame
Titrator?
Solaris
Titrator
Afterstandardizingthemeasuringsystemandeliminatingtheabove
possiblevariations,wehadcorrelationstudywithoursupplier.
Measure

16. 16
5.5
5.6
5.7
5.8
5.9
6
6.1
6.2
6.3
Sample1Sample2Sample3Sample4Sample5
cm³
IKD–MTPcorrelationonCompressionVolume
46ZD11FBwk2/09
USL
LSL
MTP1
MTP2
MTP3
IKD1
IKD2
IKD3
Thecorrelationstudy
showsthereisstillhad
differencesamong
measurementsafter
thosecorrective
actions.
Measure
TheresultshowsoursupplierresultsstilldidnotcorrelatewithMTP’s.

17. 17
Resultsfor:46ZD11Stdcal
Two-SampleT-TestandCI:IKD,MTP
Two-sampleTforIKDvsMTP
NMeanStDevSEMean
IKD156.05600.04730.012
MTP155.84800.03300.0085
Difference=mu(IKD)-mu(MTP)
Estimatefordifference:0.2080
95%CIfordifference:(0.1775,0.2385)
T-Testofdifference=0(vsnot=):T-Value=
13.96P-Value=0.000DF=28
BothusePooledStDev=0.0408
Pvalueis<0.05whichmeansthemeasurementsweredifferent.
Measure
Conclusion:Therewerestillbigdifferences

18. 18
ProcessingMap
MeasuringSystem
Mediaused
inapparatus
Procedure&
Standard
VerifyfixtureUsingSame
Titrator?
Solarus
Titrator
Atthispoint,theonlyotherpossiblecauseofvariationanderrorwas
thevolumemeasuringinstrument(SolarusTitrator)itself.
Measure

19. 19
Thisprojectconcentratedonthefollowingareastoinvestigatetherootcausesand
determinepossiblesolutions:
Didthistitrator’soriginalmanufacturer’sspecificationmeetourvolumerange
requirement?
Didoriginaltitratorcalibrationprocesscontributetoerrorinthemeasurement
itself,specificallyatthelowerpotionofinstrumentrange?
Isthereanyalternatemethodorinstrumentcanbeusedtomeasurevolume?
Inordertoinvestigatethosepossiblerootcauses,aseriesofexperimentswere
carriedout.
SolarusTitratorMeasuringSystemAnalysis
Analysis

20. 20
SolarusTitratorwithStihl
CalibrationWorkInstruction
Solarus
Tolerance
StihlWI–
Calibratebefore
use
OriginalLinear
issue
Weight,density
issue
Analysis
Rootcause#1Rootcause#2Rootcause#3Rootcause#4
SolarusTitratorMeasuringSystemAnalysisRootCauses

21. 21
ProcedureofDigitalSolarusTitrator
SOLARUSApparatusAnalyticalBalanceGraduatedCylinderIsopropylAlcohol
SolarusTitratorwithStihlCalibrationWorkInstruction
Analysis

22. 22
ProcedureofDigitalSolarusTitrator
–FillthegraduatedcylinderwithIsopropylAlcoholusingtheSOLARUS
titrationapparatusto20ml.RecordtheSOLARUSdigitalreading
graduatedcylinderreading,whichis(ApparatusreadingA)=20ml
–WeighthecylinderontheBalanceandrecordthereadingas“B”.
–ThespecificgravityofIsopropylAlcoholis0.786,whichis“C”.
–Divide“B/C“togettheresultant“D”,(D=B/C).
–Subtracttheabovevalue“A”from“D”,(A-D).Thedifference∆=A–D.
–If∆<+/-0.02ml,theapparatusshouldnotbeadjusted.
–If∆>+/-0.02ml,followingCalibrationinstructionsasexplainedaboveor
intheSOLARUSInstructionManual.
SolarusTitratorwithStihlCalibrationWorkInstruction
Analysis

23. 23
Digitalweightscale
Tolerance:
100g+/-0.1mg
GraduatedTitrator
Tolerance:
10ml+/-0.02
SolarusDigital
Titrator
Tolerance:
5ml+/-0.06
5mlFlask
Tolerance:
5ml+/-0.02
ToleranceofInstruments
Analysis
Rootcause#1
12
43

24. 24
DigitalSolarusTitratorSpecification
Instrumenttoleranceis+/-0.06ml
Ourcylindersvolumerangesareshownbelow.
Theinstrumenttoleranceisnotfitforthesekindofmeasurements.Thetolerance
usedupalmost1/3ofvolumerange.
Part#Spec./lowSpec./highRange
37ZD62.873.270.4
38ZD263.033.450.42
40ZD383.573.870.3
43ZD13.724.160.44
46ZD115.736.170.44
Ave.0.4
Analysis
0.12/0.4=30%
ToleranceofInstrumentsRootcause#1

25. 25
ThisGageR&RStudyalsoshowsthisinstrumentisnotagoodchoice.
Part-to-PartReprodRepeatGageR&R
80
40
0
Percent
%Contribution
%StudyVar
0.04
0.02
0.00
Sample Range
_
R=0.016
UCL=0.04119
LCL=0
DonJoeYun
5.000
4.975
4.950
Sample Mean
__
X=4.96611
UCL=4.98248
LCL=4.94974
DonJoeYun
10987654321
5.05
5.00
4.95
Flask__1
YunJoeDon
5.05
5.00
4.95
Operator
10987654321
5.000
4.975
4.950
Flask__1
Average
Don
Joe
Yun
Operator
Gagename:
Dateofstudy:
Reportedby:
Tolerance:
Misc:
ComponentsofVariation
RChartbyOperator
XbarChartbyOperator
SMeasurebyFlask__1
SMeasurebyOperator
Operator*Flask__1Interaction
GageR&R(ANOVA)forSMeasure
Processtolerance=0.12
StudyVar%StudyVar%Tolerance
SourceStdDev(SD)(6*SD)(%SV)(SV/Toler)
TotalGageR&R0.01108670.06652052.9755.43
Repeatability0.01022680.06136148.8651.13
Reproducibility0.00428120.02568720.4521.41
Operator0.00428120.02568720.4521.41
Part-To-Part0.01775380.10652384.8288.77
TotalVariation0.02093110.125587100.00104.66
Thisshouldbe<30%
Analysis

26. 26
Solarus
Tolerance
StihlWI–
Calibrate
beforeuse
Original
Linearissue
Weight,
densityissue
Graduate
Titrator
Analysis
Rootcause#2Rootcause#3Rootcause#4Rootcause#1
SolarusTitratorwithStihl
CalibrationWork
Instruction
WefoundaGraduatedtitratorwithatoleranceof
+/-0.02.(P23photo#3)

27. 27
Analysis
GraduateTitratorvs.SolarusDigitalTitrator
Test#1
Titrated20timesinto10pieces5mlflaskswitheachTitrators.
Recordedweightedeachflasksbyusingdigitalweightscale(P23photo#1)
RungraphsinMini-tabforI-MRruncharttoshowvariationdifferencesbetweentwoTitrators.
RungraphsinMini-tabforF-testtoshowdifferentstandarddeviationsoftwo.
Test#2
•TitratedbothSolarusandGraduatedTitratorsfrom1to10mlandweighted.
•Calculatedvolumefromeachweightedvalue.
•Calculatederrorbysubtracteditfrominstrumentface“reading”.
•Graphedbotherrorsfrom1mlto10mlscaleforbothtitrators.
Twotestswerecarriedouttoapproveifthegraduatedtitratorismeet
ourmeasurementrequirements.

28. 28
Test1result:
TestforEqualVariances:W3/4/11versus
Instr.
95%Bonferroniconfidenceintervalsforstandard
deviations
Instr.NLowerStDevUpper
Solarus200.00489300.00667880.0103474
Titritor200.01252040.01708960.0264769
F-Test(NormalDistribution)
Teststatistic=0.15,p-value=0.000
Levene'sTest(AnyContinuousDistribution)
Teststatistic=3.70,p-value=0.062
Analysis
Pvalueis<0.05whichmeans2
populationmeansweredifferent.
GraphalsoshowSolarustitratorhas
lessvariationanderrors.

29. 29
TheresultshowsGraduatedtitratorhaslargeerrors
comparetoSolarus
Test2Result
0.0000
0.0100
0.0200
0.0300
0.0400
0.0500
0.0600
0.0700
12345678910
Errors
SolarusVsGraduatedTitrators
Titratedfrom1mlto10ml
GraduT
SolarusT
Graduated
Titrator
Solarus
Titrator
Analysis

30. 30
Two-SampleT-TestandCI:G-Titrator_1,S-
Titrator
Two-sampleTforG-Titrator_1vsS-Titrator
NMeanStDevSEMean
G-Titrator_1100.03750.01430.0045
S-Titrator100.015990.009420.0030
Difference=mu(G-Titrator_1)-mu(S-Titrator)
Estimatefordifference:0.02148
95%CIfordifference:(0.01010,0.03285)
T-Testofdifference=0(vsnot=):T-Value=3.97
P-Value=0.001DF=18
BothusePooledStDev=0.0121
Conclusion:
TheSolarisDigitalTitratorgivesaprecisedigitalreadingwhichresultsin
fewervariationsinmeasurementsandiseasytooperate.
Pvalueis<0.05whichmeans2populationmeansweredifferent.
GraphalsoshowSolarustitratorhaslessvariationanderrors.
Analysis

31. 31
Solarus
Tolerance
StihlWI–
Calibrate
beforeuse
Original
Linearissue
Weight,
densityissue
Graduate
Titrator
Analysis
Rootcause#2Rootcause#3Rootcause#4
SolarusTitratorwithStihl
CalibrationWorkInstruction
Rootcause#1
SolarusTitratorMeasuringSystemAnalysisRootCauses

32. 32
Conclusion:
DigitalSolarusTitratoristheonlychoiceforus.
Analysis
SinceGraduatedtitratorisnotaoption,soSolarustitratorisouronlychoice
forvolumeinspection.
Nowwehavetofocusonpotentialrootcauses#2,#3&#4.
Throughfollowinganalysisandexperimentswemaycanbeabletouse
thisDigitalSolarusTitratorwithoutorlessmeasurementvariations.

33. 33
Solarus
Tolerance
StihlWI–
Calibrate
beforeuse
Original
Linearissue
Weight,
densityissue
ROOTCAUSEANAYLSIS
Graduate
Titrator
Analysis
Rootcause#2Rootcause#3Rootcause#4
SolarusTitratorwithStihl
CalibrationWorkInstruction
Rootcause#1

34. 34
Inordertoinvestigatethisrootcause,followingexperimentwasconducted:
–CalibratedSolarusTitratortoStihlStandard(∆>+/-0.02ml)Before
measurements.
–Titratedinto10pieces5MLflasks.
–RecordedthereadingfromSolarusdigitalscreen.
–RunMini-TabonI-MRchartandF-Test.
–Reviewedchartstoseehowthisdailycalibrationinfluencedtothisinstrumentand
ourcylindermeasurements.
StihlWI–CalibratebeforeeachuseRootcause#2
Testshowseachtimehastobeadjusted.Inthiscasethe
adjustmentswere(19.93ml,20.05ml,&20.03ml).
Accordingtomanufacturetolerance(+/-0.06)thereisnot
necessaryforanyadjustment.

35. 35
28252219161310741
5.05
5.00
4.95
Observation
Individual Value
_
X=4.986
UCL=5.0474
LCL=4.9246
28252219161310741
0.075
0.050
0.025
0.000
Observation
Moving Range
__
MR=0.0231
UCL=0.0755
LCL=0
5
1
I-MRChartofV-reading
Project:Untitled
StihlWI–CalibratebeforeeachuseRootcause#2
Itshowsprocessisstablewith3daysstdcal.Itshowsprocessisstablewith3daysstdcal.
Labtest:
Testsweredone3days10
partsperday.Calibrated
eachday.
Testresult:
Theinstrument’s
processingisstableafter3
daysofmeasurementwith
dailycalibration.Which
meanstheinstrumenttolerance
is+/-0.06,whenyoucalibrated
to+/-0.02ISNOTeffecttothis
instrument.
Itshowsprocessisstablewith3daysstdcal.Itshowsprocessisstablewith3daysstdcal.
Analysis

36. 36
stdday3cal
stdday2cal
stdday1cal
0.050.040.030.020.01
Std cal 3 days
95%BonferroniConfidenceIntervalsforStDevs
TestStatistic1.25
P-Value0.535
TestStatistic0.27
P-Value0.767
Bartlett'sTest
Levene'sTest
TestforEqualVariancesforV-reading
Project:Untitled
Whichmeansifcalibrated
beforeeachdayoreach
timeuse,thereareno
differencesinmeasurement
variationforthis
instrument.
Buttheinstrumentruns
insideitscontrollimitdid
notmeanthisdaily
calibrationwillnotaffect
themeasurementifthe
samepartismeasured3
daysinarowaccordingto
thefollowingdata.
StihlWI–CalibratebeforeeachuseRootcause#2
ThisP>.05whichmeansvariationissamedaytoday
Analysis

37. 37
Pvalueis<0.05whichmeansatleast2populationmeansweredifferent.
One-wayANOVA:V-readingversusStdcal3days
SourceDFSSMSFP
Stdcal3days20.0060200.0030107.320.003
Error270.0111000.000411
Total290.017120
S=0.02028R-Sq=35.16%R-Sq(adj)=30.36%
Individual95%CIsForMean
Basedon
PooledStDev
LevelNMeanStDev--------+---------+---------
+---------+-
stdday1cal104.96600.0241(--------*-------)
stdday2cal104.99500.0165(--------*----
----)
stdday3cal104.99700.0195(-------*----
----)
--------+---------+---------+---------+-
4.9654.9804.9955.010
PooledStDev=0.0203
IndividualValuePlotofV-readingvsStdcal3days
Analysis
StihlWI–CalibratebeforeeachuseRootcause#2

38. 38
StihlWI–Calibratebeforeeachuse
28252219161310741
5.05
5.00
4.95
4.90
Observation
Individual Value
_
X=4.997
UCL=5.0443
LCL=4.9497
stdday1calstdday2calstdday3cal
28252219161310741
0.100
0.075
0.050
0.025
0.000
Observation
Moving Range
__
MR=0.0178
UCL=0.0581
LCL=0
stdday1calstdday2calstdday3cal
I-MRChartofV-readingbyStdcal3days
Rootcause#2
Analysis
28252219161310741
5.05
5.00
4.95
Observation
Individual Value
_
X=4.986
UCL=5.0474
LCL=4.9246
28252219161310741
0.075
0.050
0.025
0.000
Observation
Moving Range
__
MR=0.0231
UCL=0.0755
LCL=0
5
1
I-MRChartofV-reading
Project:Untitled
Chartwithstagesshowsmeanweredifferenton3
days
ChartwithoutstageshowsTitratorrunswithin
itscontrollimit.

39. 39
Conclusion:Calibrationforeachusewillcontributetoerror.
Resultsshowfor3consecutivedays,theinstrumenthastobeadjusted3times.
Thismeanssamecylindermeasuredin3dayswillget3differentreadings.The
differencesofmeanis4.997-4.966=0.031whichusedupabout
0.031/0.4=7.8%oftotalcylindervolumerange.15%ofcylindersmeasuredout
ofspecificationwereeventuallyinspecification.
AccordingtoStihl’s(ourcustomer)inspectionworkinstruction,theinstrument
hastobecalibratedbeforeeachuse.
WhenwespokewiththeSolarismanufacturerexpert,theyrecommendedthat
theinstrumentbecalibratedonlyonceayear.
StihlWI–CalibratebeforeeachuseRootcause#2
Analysis

40. 40
Solarus
Tolerance
StihlWI–
Calibratebefore
use
Original
Linearissue
Weight,
densityissue
ROOTCAUSEANAYLSIS
Graduate
Titrator
Analysis
Shouldnot
calibrate
beforeeachuse
Rootcause#2Rootcause#3Rootcause#4
SolarusTitratorwithStihl
CalibrationWorkInstruction
Rootcause#1

41. 41
–Inordertoinvestigatethisrootcause,followingexperimentwasconducted:
CalibratedSolarusTitratortoStihlstandard.
Titrated10timeseachfrom1mlto10ml.
Weighedeachmeasurementondigitalweightscale.
ConvertedweighttovolumebyusingthedensityratefromIsopropyl
Alcoholsupplier(suppliercatalog)–0.785g/mlinthiscase.
Calculated“true”densityratebyusing10measuredweights–0.781g/ml
inthiscase.
Errorsasaresultofusingdifferentdensityrateareshownonfollowing
graph.
OriginalLinearissueRootcause#3
Analysis

42. 42
Conclusion:DENSITYusedincalibrationincreasedlinearerror
Thetestresultshows:
1.Thedensityusedforcalculationfrom
weighttovolumewasfromcatalogof
mediausedinthisinstrument.Itdid
notreflecttruevalueofthismedia
whichintroducederrorinto
calibration.
2.Thevaluecanbeshiftedawayupto
0.09ml.Whichistakingabout
0.09/0.4=22.5%ofournormal
measuringrange.
Analysis
StandardCalibration
-0.1000
-0.0800
-0.0600
-0.0400
-0.0200
0.0000
0.0200
0.0400
12345678910
scale
Volume error
OriginalLinearissueRootcause#3
ML

43. 43
Solarus
Tolerance
StihlWI–
Calibrate
beforeuse
Original
Linearissue
Weight,
densityissue
ROOTCAUSEDANAYLSIS
Graduate
Titrator
Analysis
Shouldnot
calibrate
beforeeachuse
Rootcause#2Rootcause#3Rootcause#4
SolarusTitratorwithStihl
CalibrationWorkInstruction
Rootcause#1
Errorwasbuilt
inasvolume
wentup

44. 44
Weight,densityissueRootcause#4
–Inordertoinvestigatethisrootcause,thefollowingexperimentwas
conducted:
CalibratedSolarusTitratortoStihlstandard.
Using10pcs5mlflasks,threepersonseachtitrated3timesforeach
flask.Therewereatotalof3peoplex3timesx10flasks=90readings.
Total90readingsareshownonthefollowinggraph.

45. 45
5.065.045.025.004.984.964.944.92
LSLUSL
LSL4.94
Target*
USL5.06
SampleMean4.96611
SampleN90
StDev(Within)0.0182285
StDev(Overall)0.020095
ProcessData
Cp1.10
CPL0.48
CPU1.72
Cpk0.48
Pp1.00
PPL0.43
PPU1.56
Ppk0.43
Cpm*
OverallCapability
Potential(Within)Capability
PPM<LSL11111.11
PPM>USL0.00
PPMTotal11111.11
ObservedPerformance
PPM<LSL76010.42
PPM>USL0.13
PPMTotal76010.55
Exp.WithinPerformance
PPM<LSL96905.82
PPM>USL1.49
PPMTotal96907.31
Exp.OverallPerformance
Within
Overall
ProcessCapabilityofSMeasure
Weight,densityissue
Thedensityrateinvolvedincalibrationmovedtruevaluefrom5.00mlto4.966ml.
Whichusedupabout0.034/0.40=8.5%oftotalcylindervolumerange.
Rootcause#4
Analysis
Conclusion:
DENSITYusedincalibrationmovedreadingfromtruevalue.

46. 46
Solarus
Tolerance
StihlWI–
Calibrate
beforeuse
Original
Linearissue
Weight,
densityissue
ROOTCAUSEDANAYLSIS
Graduate
Titrator
Analysis
Shouldnot
calibratebefore
eachuse
Rootcause#2Rootcause#3Rootcause#4
Errorwasbuilt
inasvolumego
up
Densityused
fromcatalog
givenerror
Shouldnot
calibrate
beforeeachuse
SolarusTitratorwithStihl
CalibrationWorkInstruction
Rootcause#1

47. 47
PossibleAlternatecalibrationmethods–whichdonotinvolve
weight:
1.Graduatedtitrator
–Thismethodhasbeenalreadyruledoutbecauseofdifficultyofreading
whichaddedextravariations.(Asshownpreviously,thisisthesamereason
itisnotsuitablefordailyvolumeinspection).
2.Flaskmightbebestoption.
–Chooseflasksizethatclosetocastingvolumerangetominimizelinear
error.
–Hastightertolerance+/-0.02.
–Noweightinvolvedinaddonerror.
–Easytooperatewithlessvariation.
Improvement

48. 48
CalibrateSolarusTitratorbyusingFlask
Wedecidedtouse10pieces5MLflasksascalibrationtool:
1.5mListheclosestsizeavailableonmarketandcanbeeasily
replacedifneeded.
2.5MLisclosetotheourvolumemeasuringrange.
3.Ithastighttoleranceof+/-0.02
4.Easytoread.
5.Verygoodrepeatability(refertolategageR&Rstudyresults)
Improvement

49. 49
ProcedureforCalibrationUsingFlasks
1.Measure10timesforeach5ML
flask.
2.Average10readings.
3.Iftheaveragereading>+/-
0.02mL,theadjustmentis
requested.
4.Adjustment=(Ave.reading–
5ml)x4.
5.Re-measure10timesforeach
5MLflaskagaintoverify
Improvement

50. 50
Solarus
Tolerance
StihlWI–
Calibratebefore
use
OriginalLinear
issue
Weight,density
issue
ROOTCAUSESANDCORRECTIVEACTION
Graduate
Titrator
Shouldnot
calibratebefore
eachuse
Rootcause#2Rootcause#3Rootcause#4
Errorwasbuilt
inasvolume
wentup
Densityused
fromcatalog
givenerror
Noneedto
calibrate
beforeeachuse
Improvement
SolarusTitratorwithStihl
CalibrationWorkInstruction
Rootcause#1

51. 51
Labtest:
1.SolarusTitratorcalibrated
withnewcalibrationmethod
(Flaskmethod).
2.Verified3daysinarow
byusing5MLflask.
Theresult:
Thegraphshowseachday
resultstayedthesame.
Thereforenoadjustmentsto
theinstrumentisneeded.
Improvement
CorrectiveActiontoRootcause#2
28252219161310741
5.050
5.025
5.000
4.975
4.950
Observation
Individual Value
_
X=5.003
UCL=5.0385
LCL=4.9675
Day1Day2Day3
28252219161310741
0.060
0.045
0.030
0.015
0.000
Observation
Moving Range
__
MR=0.01333
UCL=0.04356
LCL=0
Day1Day2Day3
1
1
I-MRChartofFlaskCal_1by3Days

52. 52
CorrectiveActiontoRootcause#2
ThisP>.05whichmeansvariationissamedaytoday
Improvement

53. 53
Day3Day2Day1
5.04
5.03
5.02
5.01
5.00
4.99
4.98
4.97
3Days
Flask Cal_1
BoxplotofFlaskCal_1
One-wayANOVA:FlaskCal_1versus3Days
SourceDFSSMSFP
3Days20.0001270.0000630.250.781
Error270.0068600.000254
Total290.006987
S=0.01594R-Sq=1.81%R-Sq(adj)=0.00%
Individual95%CIs
ForMeanBasedon
PooledStDev
LevelNMeanStDev-----+---------+---
------+---------+----
Day1104.99800.0175(--------------*---
-----------)
Day2105.00100.0152(-------------
*--------------)
Day3105.00300.0149(-----------
---*--------------)
-----+---------+---
------+---------+----
4.99104.9980
5.00505.0120
PooledStDev=0.0159
P-Value>0.05,whichmeanstherearenodifferencesamongthe3daysof
measurements.
Improvement
CorrectiveActiontoRootcause#2
Conclusion:
Flaskcalibrationdidnothaveanyvariationfromdaytodaycalibration
whichmeansadjustmentsarenotneeded.

54. 54
CorrectiveActiontoRootcause#3
-0.1000
-0.0800
-0.0600
-0.0400
-0.0200
0.0000
0.0200
0.0400
12345678910
WithnewCalibration
theerroratcylinders
volumerangeis<
0.01ml
Volume Error
Volumemeasuredfrom1mlto10ml
Newcalibration
Oldcalibration
Improvement
Labtest:
1.SolarusTitratorcalibrated
withnewcalibrationmethod
(Flaskmethod).
2.Titrated10timesfrom1ml
to10ml
Theresult:
Comparedtoresultwithold
calibratedsystem(page
42),thegraphshowswith
newcalibrationmethodhas
lesserrors.Theerrorsat
cylindervolumerangeis<
0.01ml.

55. 55
Two-SampleT-TestandCI:OldCal,New
Cal
Two-sampleTforOldCalvsNewCal
NMeanStDevSEMean
OldCal10-0.04060.03300.010
NewCal100.00400.01220.0039
Difference=mu(OldCal)-mu(NewCal)
Estimatefordifference:-0.0446
95%CIfordifference:(-0.0680,-0.0212)
T-Testofdifference=0(vsnot=):T-Value
=-4.00P-Value=0.001DF=18
BothusePooledStDev=0.0249
Pvalueis<0.05whichmeans2populationmeansweredifferent.
GraphalsoshowNewcalibrationhaslessvariationanderrors.
Conclusion:
NewcalibrationmethodeliminatederrorcausedbyOldcalibration
methodwhichinvolvedinweightanddensity.
Improvement

56. 56
5.065.045.025.004.984.964.94
LSLUSL
LSL4.94
Target*
USL5.06
SampleMean5.00178
SampleN90
StDev(Within)0.0202207
StDev(Overall)0.0200324
ProcessData
Cp0.99
CPL1.02
CPU0.96
Cpk0.96
Pp1.00
PPL1.03
PPU0.97
Ppk0.97
Cpm*
OverallCapability
Potential(Within)Capability
PPM<LSL0.00
PPM>USL22222.22
PPMTotal22222.22
ObservedPerformance
PPM<LSL1124.67
PPM>USL1992.59
PPMTotal3117.25
Exp.WithinPerformance
PPM<LSL1021.57
PPM>USL1828.08
PPMTotal2849.65
Exp.OverallPerformance
Within
Overall
ProcessCapabilityofFMeasure
5.065.045.025.004.984.964.944.92
LSLUSL
LSL4.94
Target*
USL5.06
SampleMean4.96511
SampleN90
StDev(Within)0.0185274
StDev(Overall)0.0205128
ProcessData
Cp1.08
CPL0.45
CPU1.71
Cpk0.45
Pp0.98
PPL0.41
PPU1.54
Ppk0.41
Cpm*
OverallCapability
Potential(Within)Capability
PPM<LSL11111.11
PPM>USL0.00
PPMTotal11111.11
ObservedPerformance
PPM<LSL87652.72
PPM>USL0.15
PPMTotal87652.87
Exp.WithinPerformance
PPM<LSL110444.19
PPM>USL1.87
PPMTotal110446.06
Exp.OverallPerformance
Within
Overall
ProcessCapabilityofSMeasure
Improvement
CorrectiveActiontoRootcause#4
Labtest:
1.SolarusTitratorcalibratedwithnewcalibrationmethod(Flaskmethod).
2.Using10pcs5mlflasks,threepersonseachtitrated3timesforeachflask.Therewerea
totalof3peoplex3timesx10flasks=90readings.Total90readings.
Theresult:
Comparedtheresultwitholdcalibratedsystem(page45),theprocesscapabilityandT-test
showssigmaandstandarddeviationwereimprovedwithnewcalibrationmethod.
BeforeAfter

57. 57
Two-sampleTforFMeasurevsS
Measure
NMeanStDevSEMean
FMeasure905.00180.0200
0.0021
SMeasure904.96510.0205
0.0022
Difference=mu(FMeasure)-mu(S
Measure)
Estimatefordifference:0.03667
95%CIfordifference:(0.03070,
0.04263)
T-Testofdifference=0(vsnot=):T-
Value=12.13P-Value=0.000DF=
178
BothusePooledStDev=0.0203SMeasureFMeasure
5.08
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92
Data
BoxplotofFMeasure,SMeasure
P-Value<0.05,whichmeanstherearedifferencesbetweenthe2measurements.
CorrectiveActiontoRootcause#4
Improvement
Meanismovetotarget

58. 58
Improvement
DATAHIGHLIGHT
BeforeAfter
Z-Bench(Sigmavalue)1.33.16
StDev0.0200.017
Mean4.966114.99989
CorrectiveActiontoRootcause#4
Conclusion:
Newcalibrationimprovedsigmavalueandmovemeanto“true”value.

59. 59
StihlWI–
Calibrate
beforeuse
OriginalLinear
issue
Weight,density
issue
Rootcause#2Rootcause#3Rootcause#4
Errorwasbuilt
inasvolumego
up
Densityused
fromcatalog
givenerror
Shouldnot
calibrate
beforeeachuse
ROOTCAUSESANDCORRECTIVEACTION
Improvement
1.FlaskCalibrationMethod
2.NewWorkInstruction
ChangeWork
Instruction
RootCauses
Analysis&
Approve
Corrective
Actions

60. 60
Itemsthatneedtobeupdatedandcontrolled
MTPimplementedNewCalibrationwork
instruction
Trainingtheinspectoronnewverification
methodbeforeeachmeasuring.
IKD(supplier)alsoimplementedNew
Calibrationmethod
UpdatedISOsystemtoreflectthenewWI
ContinuemonitoringproductionandCustomer
returns
Control

61. 61
ChangingproceduretocorrelatedtoStihlrequirements
∆>+/-0.02ml
SolarusTitrator
calibrationprocedure
Calibratedbefore
eachuse.(Calibrated
at20mlSolarus
standard)
STIHL
Incoming
inspection
∆>+/-0.02ml
MAHLEnew
calibrationMethod
Nochangedaytoday(test
approved).SoNO
adjustmentneeded(New
methodcalibratedat5ml
andourusedataround5ml
area)
MAHLENew
Calibration
Method

62. 62
AfterIKD(supplier)adoptedFlaskCalibrationmethod,MTPandIKDhad
correlationstudyon37ZD26.Thefollowingresultsshowsimprovement.
BeforeAfter
5.5
5.6
5.7
5.8
5.9
6
6.1
6.2
6.3
Sample1Sample2Sample3Sample4Sample5
cm³
46ZD11
CompressionVolumeComparisonUS
L
LS
L
MT
P1
MT
P2
MT
P3
IK
D1
IK
D2
IK
D3
Control
2.7
2.8
2.9
3
3.1
3.2
3.3
Sample1Sample2Sample3Sample4Sample5
cm³
37ZD26
CompressionVolumeComparison
US
L
LSL
MT
P1
MT
P2

63. 63
Two-SampleT-TestandCI:IKD,MTP
Two-sampleTforIKDvsMTP
NMeanStDevSEMean
IKD156.05600.04730.012
MTP155.84800.03300.0085
Difference=mu(IKD)-mu(MTP)
Estimatefordifference:0.2080
95%CIfordifference:(0.1775,0.2385)
T-Testofdifference=0(vsnot=):T-Value
=13.96P-Value=0.000DF=28
BothusePooledStDev=0.0408
Before
P-Value<0.05,whichmeansmeasurementresultsweredifferentbetween
IKDandMTPonsamecylinders.
Control

64. 64
Two-SampleT-TestandCI:IKD,MTP
Two-sampleTforIKDvsMTP
NMeanStDevSEMean
IKD152.95600.04000.010
MTP152.93070.03280.0085
Difference=mu(IKD)-mu(MTP)
Estimatefordifference:0.0253
95%CIfordifference:(-0.0020,
0.0527)
T-Testofdifference=0(vsnot=):T-
Value=1.90P-Value=0.068DF=28
BothusePooledStDev=0.0366
After
P-Value>0.05,whichmeansmeasurementresultsweresamebetween
IKDandMTPonsamecylinders.
Control

65. 65
YearStihlreturn/ScrapPotential
Loss(DeviationIssued)
SigmaValue
2007$117,456.68$532,100.003yearsaverage1.507
2008$1,767.00$184,500.003yearsaverage1.507
2009$33,923.13$186,235.003yearsaverage1.507
2010$0.00$0.00Sigmavalueis6since
IKD&MTPadaptednew
measuringsystem
ProjectGoalandSavings:
AfterMTPandIKDadaptedtheNewcalibrationsystemin2010thereisno
defectsfound.

66. 66
Summary
OriginalSolarusDigitalTitratorhasloosetolerance(+/-0.06)andshouldnotbeusedasacylinder
volumeinspectiontool.
Stihl(customer)establishedcalibrationprocedureforcalibratingbeforeeachuse.However,this
methodactuallycontributedmoreerrortodailymeasurements.
Theoriginalcalibrationmethodinvolveddensityofmediaandweightwhichalsocontributedto
errorinmeasurements.
Theseerrorsresultedinfalserejectionsfromourcustomeranduncorrectedadjustmentfromour
castingsupplier,aswellascorrelationissuesamongthethreeparties.
Sincetherearenootherbetterinstrumentsavailable,wefoundabettercalibrationmethodand
procedurethateliminatedaboveerrors.
Throughthisproject,weapprovedthisnewcalibrationmethodthatcorrectedtheissue.
Thetestdatashowsthatmeasurementswerenotonlyclosetothe“true”valuebutalsocorrelated
wellwithoursupplier’smeasurementsusingthesamenewmethod.
WesuggestedthatStihlshouldreviewthisprojectandadaptthemethodtoeliminateallfalse
rejectionsofcompressionvolumemeasurementsinfutureinspections.

67. 67
LessonLearned:
Howtoapplythesequalityanalysismethodsintoourdailyproductionissues.
Howtoapproachtheproblem.
Howtoorganizeandmanagetheproject.
HowtouseMiniTabasapowerfulandefficienttoolforanalyzingdata.
Howtodetermine,stepbystep,therootcauseoftheproblem.
HowtoclearlypresentresultstotheaudienceusingsuchtoolsasPowerPoint.